ELISA kits are widely used in medical and research laboratories for detecting and quantifying substances such as peptides, proteins, antibodies, and hormones. They are essential in diagnosing infectious diseases like HIV, hepatitis, and Lyme disease by identifying specific antigens or antibodies in blood samples. These kits are also used in food industry testing to detect allergens such as peanuts or gluten. In pharmaceutical development, ELISA kits help monitor immune responses during clinical trials. Their high sensitivity and specificity make them valuable tools in both clinical diagnostics and biomedical research.